If the hatch release motor whirs and the hatch doesn't open, you can buy just the little plastic piece that broke from prototypist on etsy or shapeways (I think it's about $4 plus shipping):
littleblueplasticpart1 by prototypist on Shapeways
littleblueplasticpart1 by prototypist on Etsy
(contact him and he'll make you one, I don't think he keeps them in stock since it's 3d printed)
If the hatch motor makes no noise at all, there's a plug that sometimes gets corroded that runs around the outside of the hatch glass back to the main body shell.
More info on the connector and the little plastic part:
TRUNK NOT OPENING !!!!!!!!!!! - Page 3 - Insight Central: Honda Insight Forum